Add host.arch attribute to HostDetector and update tests

src/OpenTelemetry.Resources.Host/CHANGELOG.md

@@ -5,6 +5,10 @@
 * Updated OpenTelemetry core component version(s) to `1.13.0`.
   ([#3158](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/3158))
 
+* Added support for the `host.arch` resource attribute in `HostDetector`
+  for .NET only.
+  ([#3147](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/3147))
+
 ## 1.12.0-beta.1
 
 Released 2025-May-06

src/OpenTelemetry.Resources.Host/HostDetector.cs

@@ -76,6 +76,29 @@ internal HostDetector(
         this.getWindowsMachineId = getWindowsMachineId;
     }
 
+#if !NETFRAMEWORK
+    public static string? MapArchitectureToOtel(Architecture arch)
+    {
+        return arch switch
+        {
+            Architecture.X86 => "x86",
+            Architecture.X64 => "x64",
+            Architecture.Arm => "arm32",
+            Architecture.Arm64 => "arm64",
+#if NET
+            Architecture.S390x => "s390x",
+            Architecture.Armv6 => "arm32",
+            Architecture.Ppc64le => "ppc64",
+
+            // following architectures do not have a mapping in OTEL spec https://github.com/open-telemetry/semantic-conventions/blob/v1.37.0/docs/resource/host.md
+            Architecture.Wasm => null,
+            Architecture.LoongArch64 => null,
+#endif
+            _ => null,
+        };
+    }
+#endif
+
     /// <summary>
     /// Detects the resource attributes from host.
     /// </summary>
@@ -84,17 +107,29 @@ public Resource Detect()
     {
         try
         {
-            var attributes = new List<KeyValuePair<string, object>>(2)
+            var attributes = new List<KeyValuePair<string, object>>(3)
             {
                 new(HostSemanticConventions.AttributeHostName, Environment.MachineName),
             };
+
             var machineId = this.GetMachineId();
 
             if (machineId != null && !string.IsNullOrEmpty(machineId))
             {
                 attributes.Add(new(HostSemanticConventions.AttributeHostId, machineId));
             }
 
+#if !NETFRAMEWORK
+            var arch = MapArchitectureToOtel(RuntimeInformation.OSArchitecture);
+            if (arch != null)
+            {
+                attributes.Add(new(HostSemanticConventions.AttributeHostArch, arch));
+            }
+#endif
+#if NET471_OR_GREATER
+#error Architecture is available in .NET Framework 4.7.1+, enable it when we move to that as minimum supported version
+#endif
+
             return new Resource(attributes);
         }
         catch (InvalidOperationException ex)

src/OpenTelemetry.Resources.Host/HostSemanticConventions.cs

@@ -7,4 +7,5 @@ internal static class HostSemanticConventions
 {
     public const string AttributeHostName = "host.name";
     public const string AttributeHostId = "host.id";
+    public const string AttributeHostArch = "host.arch";
 }

src/OpenTelemetry.Resources.Host/README.md

@@ -54,7 +54,10 @@ using var loggerFactory = LoggerFactory.Create(builder =>
 The resource detectors will record the following metadata based on where
 your application is running:
 
-- **HostDetector**: `host.id` (when running on non-containerized systems), `host.name`.
+- **HostDetector**:
+  - `host.arch` (supported only on .NET),
+  - `host.id` (when running on non-containerized systems),
+  - `host.name`.
 
 ## References
 

test/OpenTelemetry.Resources.Host.Tests/HostDetectorTests.cs

@@ -51,10 +51,20 @@ public void TestHostAttributes()
 
         var resourceAttributes = resource.Attributes.ToDictionary(x => x.Key, x => (string)x.Value);
 
+#if NET
+        Assert.Equal(3, resourceAttributes.Count);
+#else
         Assert.Equal(2, resourceAttributes.Count);
+#endif
 
         Assert.NotEmpty(resourceAttributes[HostSemanticConventions.AttributeHostName]);
         Assert.NotEmpty(resourceAttributes[HostSemanticConventions.AttributeHostId]);
+#if NET
+        Assert.NotEmpty(resourceAttributes["host.arch"]);
+#pragma warning disable CA1308 // Normalize strings to uppercase
+        Assert.Equal(RuntimeInformation.ProcessArchitecture.ToString().ToLowerInvariant(), resourceAttributes["host.arch"]);
+#pragma warning restore CA1308 // Normalize strings to uppercase
+#endif
     }
 
 #if NET